/**
 * @file: edge_item.h 
 * Edge Widget class definition.
 */
/*
 * GUI for ShowGraph tool.
 * Copyright (c) 2009, Boris Shurygin
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
 * 
 * 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#ifndef EDGE_W_H
#define EDGE_W_H

#include "gview_impl.h"
/** size of edge control */
const qreal EdgeControlSize  = 5;

/**
 * Representation of drawable edge
 * @ingroup GUIGraph
 */
class GEdge: public AuxEdge
{
    /** Pointer to corresponding graphics item */
    EdgeItem *item_p;
    /** Graphical appearance style */
    GStyle *_style;
protected:
    /** Default constructor */
    GEdge( GGraph *graph_p, int _id, GNode *_pred, GNode* _succ);


    friend class GGraph;
    friend class Node;
public:
    /**
     * Return pointer to graph
     */
    GGraph *graph() const;

    /** Destructor */
    virtual ~GEdge();

    /**
     * Return associated graphics item
     */
    inline EdgeItem *item() const
    {
        return item_p;
    }
    /** 
     * Update DOM element
     */
    virtual void updateElement();

    /**
     * Read properties from XML
     */
    virtual void readFromElement( QDomElement elem);

    /** Overload of setNode from base class */
    inline void setNode( GNode *n, GraphDir dir)
    {
        AuxEdge::setNode( ( AuxNode *)n, dir);
    }
    /** Set predecessor */
    inline void setPred( GNode *n)
    {
        setNode( n, GRAPH_DIR_UP);
    }
    /** Set successor */
    inline void setSucc( GNode *n)
    {
        setNode( n, GRAPH_DIR_DOWN);
    }
    /** Get node in given direction */
    GNode *node( GraphDir dir) const;
    /** Get predecessor */
    inline GNode *pred() const 
    {
        return node( GRAPH_DIR_UP);
    }
    /** Get successor */
    inline GNode *succ() const 
    {
        return node( GRAPH_DIR_DOWN);
    }
    
    /** Get real node in given direction */
    GNode* realNode( GraphDir) const;

    /** Get real predecessor */
    inline GNode* realPred() const
    {
        return realNode( GRAPH_DIR_UP);
    }
    /** Get real successor */
    inline GNode* realSucc() const
    {
        return realNode( GRAPH_DIR_DOWN);
    }

    /** Next edge in graph's list */
    inline GEdge* nextEdge()
    {
        return static_cast< GEdge *>(AuxEdge::nextEdge());
    }
    /** Next edge in give direction */
    inline GEdge* nextEdgeInDir( GraphDir dir)
    {
        return static_cast< GEdge *>(AuxEdge::nextEdgeInDir( dir));
    }
    /** Next successor */
    inline GEdge* nextSucc()
    {
        return nextEdgeInDir( GRAPH_DIR_DOWN);
    }
    /** Next predecessor */
    inline GEdge* nextPred()
    {
        return nextEdgeInDir( GRAPH_DIR_UP);
    } 
    /** Insert node of label type */
    GNode *insertLabelNode( QPointF pos);
        
    /** Set edge's style */
    inline void setStyle( GStyle *st);
    /** Get edge's style */
    inline GStyle * style() const
    {
        return _style;
    }
    /** Insert node */
    virtual AuxNode *insertNode();
    /** Make all styles the same across complex edge */
    void adjustStyles();
};
/**
 * Graphics item for visualizing a graph edge
 * @ingroup GUIGraph
 */
class EdgeItem: public QGraphicsItem
{
public:        
    /** Modes of an edge */
    typedef enum EdgeMode
    {
        ModeShow,
        ModeEdit
    } EdgeMode;

private:
    /** Graph connection */
    GEdge* edge_p;

    QPointF srcP;
    QPointF cp1;
    QPointF cp2;
    QPointF dstP;
    QPointF topLeft;
    QPointF btmRight;
    EdgeMode curr_mode;
public:
    /** Type of graphics item for edge */
    enum {Type = TypeEdge};
    /** Constructor */
    EdgeItem( GEdge *e_p);
    /** Get item type */
    int type() const
    {
        return Type;
    }
    /** Adjust edge image */
    void adjust();
    /** Get corresponding edge of the graph */
    inline GEdge* edge() const
    {
        return edge_p;    
    }
    /** Get mode */
    inline EdgeMode mode() const
    {
        return curr_mode;
    }
    /** Set mode */
    inline void setMode( EdgeMode m)
    {
        curr_mode = m;
    }
    /** Get bounding rectangle of edge image */
    QRectF boundingRect() const;
    /** Get shape of the edge */
    QPainterPath shape() const;
    /** Event handler for change */
    QVariant itemChange( GraphicsItemChange change, const QVariant &value);
    /** Paint edge */
    void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget);
    /** Event handler for mouse press */
    void mousePressEvent(QGraphicsSceneMouseEvent *event);
    /** Event handler for mouse release */
    void mouseReleaseEvent(QGraphicsSceneMouseEvent *event);
    /** Event handler for double click */
    void mouseDoubleClickEvent(QGraphicsSceneMouseEvent *event);
    /** Key press event handler */
    void keyPressEvent(QKeyEvent *event);
    /** Get predecessor in terms of graph model */
    inline GNode* pred() const
    {
        return edge()->pred();
    }
    /** Get successor in terms of graph model */
    inline GNode* succ() const
    {
        return edge()->succ();
    }
    /** Remove from scene */
    inline void remove()
    {
        setVisible( false);
        removeFromIndex();
        scene()->removeItem( this);
        edge_p = NULL;
    }
    /** Convenience routine for self edge path */
    QPainterPath selfEdgePath() const;
};

    /** Set edge's style */
inline void GEdge::setStyle( GStyle *st)
{
    if ( areNotEqP( _style, st))
    {
        if ( isNotNullP( _style))
            _style->decNumItems();
        _style = st;
        if ( isNotNullP( _style))
            _style->incNumItems();
    }
    item()->update();
}
#endif